scamper

-module(scamper@serialization).
-compile([no_auto_import, nowarn_unused_vars, nowarn_unused_function, nowarn_nomatch, inline]).
-define(FILEPATH, "src/scamper/serialization.gleam").
-export([serialize/4, deserialize/5]).
-export_type([serialization_error/0, decoded_machine/3]).

-if(?OTP_RELEASE >= 27).
-define(MODULEDOC(Str), -moduledoc(Str)).
-define(DOC(Str), -doc(Str)).
-else.
-define(MODULEDOC(Str), -compile([])).
-define(DOC(Str), -compile([])).
-endif.

?MODULEDOC(
    " JSON serialization and deserialization for scamper FSMs.\n"
    "\n"
    " Users must provide encoder/decoder functions for their custom\n"
    " state, context, and event types.\n"
).

-type serialization_error() :: {json_encode_error, binary()} |
    {json_decode_error, binary()}.

-type decoded_machine(IJC, IJD, IJE) :: {decoded_machine,
        IJC,
        IJD,
        integer(),
        integer(),
        list(scamper@history:transition_record(IJC, IJE, IJD))}.

-file("src/scamper/serialization.gleam", 43).
-spec encode_record(
    scamper@history:transition_record(IJL, IJM, IJN),
    fun((IJL) -> gleam@json:json()),
    fun((IJN) -> gleam@json:json()),
    fun((IJM) -> gleam@json:json())
) -> gleam@json:json().
encode_record(Record, State_encoder, Context_encoder, Event_encoder) ->
    gleam@json:object(
        [{<<"from"/utf8>>, State_encoder(erlang:element(2, Record))},
            {<<"event"/utf8>>, Event_encoder(erlang:element(3, Record))},
            {<<"to"/utf8>>, State_encoder(erlang:element(4, Record))},
            {<<"timestamp"/utf8>>, gleam@json:int(erlang:element(5, Record))},
            {<<"context_snapshot"/utf8>>,
                gleam@json:nullable(erlang:element(6, Record), Context_encoder)}]
    ).

-file("src/scamper/serialization.gleam", 21).
?DOC(
    " Serialize a machine's state to a JSON string.\n"
    " User must provide encoder functions for state, context, and event types.\n"
).
-spec serialize(
    scamper:machine(IJF, IJG, IJH),
    fun((IJF) -> gleam@json:json()),
    fun((IJG) -> gleam@json:json()),
    fun((IJH) -> gleam@json:json())
) -> binary().
serialize(Machine, State_encoder, Context_encoder, Event_encoder) ->
    History_json = begin
        _pipe = scamper:history(Machine),
        gleam@json:array(
            _pipe,
            fun(Record) ->
                encode_record(
                    Record,
                    State_encoder,
                    Context_encoder,
                    Event_encoder
                )
            end
        )
    end,
    _pipe@1 = gleam@json:object(
        [{<<"state"/utf8>>, State_encoder(scamper:current_state(Machine))},
            {<<"context"/utf8>>,
                Context_encoder(scamper:current_context(Machine))},
            {<<"created_at"/utf8>>, gleam@json:int(scamper:created_at(Machine))},
            {<<"entered_at"/utf8>>, gleam@json:int(scamper:entered_at(Machine))},
            {<<"history"/utf8>>, History_json}]
    ),
    gleam@json:to_string(_pipe@1).

-file("src/scamper/serialization.gleam", 110).
-spec build_machine_decoder(
    gleam@dynamic@decode:decoder(IKF),
    gleam@dynamic@decode:decoder(IKH),
    gleam@dynamic@decode:decoder(scamper@history:transition_record(IKF, IKJ, IKH))
) -> gleam@dynamic@decode:decoder(decoded_machine(IKF, IKH, IKJ)).
build_machine_decoder(State_decoder, Context_decoder, Record_decoder) ->
    gleam@dynamic@decode:field(
        <<"state"/utf8>>,
        State_decoder,
        fun(State) ->
            gleam@dynamic@decode:field(
                <<"context"/utf8>>,
                Context_decoder,
                fun(Context) ->
                    gleam@dynamic@decode:field(
                        <<"created_at"/utf8>>,
                        {decoder, fun gleam@dynamic@decode:decode_int/1},
                        fun(Created_at) ->
                            gleam@dynamic@decode:field(
                                <<"entered_at"/utf8>>,
                                {decoder, fun gleam@dynamic@decode:decode_int/1},
                                fun(Entered_at) ->
                                    gleam@dynamic@decode:field(
                                        <<"history"/utf8>>,
                                        gleam@dynamic@decode:list(
                                            Record_decoder
                                        ),
                                        fun(History) ->
                                            gleam@dynamic@decode:success(
                                                {decoded_machine,
                                                    State,
                                                    Context,
                                                    Created_at,
                                                    Entered_at,
                                                    History}
                                            )
                                        end
                                    )
                                end
                            )
                        end
                    )
                end
            )
        end
    ).

-file("src/scamper/serialization.gleam", 129).
-spec build_record_decoder(
    gleam@dynamic@decode:decoder(IKS),
    gleam@dynamic@decode:decoder(IKU),
    gleam@dynamic@decode:decoder(IKW)
) -> gleam@dynamic@decode:decoder(scamper@history:transition_record(IKS, IKW, IKU)).
build_record_decoder(State_decoder, Context_decoder, Event_decoder) ->
    gleam@dynamic@decode:field(
        <<"from"/utf8>>,
        State_decoder,
        fun(From) ->
            gleam@dynamic@decode:field(
                <<"event"/utf8>>,
                Event_decoder,
                fun(Event) ->
                    gleam@dynamic@decode:field(
                        <<"to"/utf8>>,
                        State_decoder,
                        fun(To) ->
                            gleam@dynamic@decode:field(
                                <<"timestamp"/utf8>>,
                                {decoder, fun gleam@dynamic@decode:decode_int/1},
                                fun(Timestamp) ->
                                    gleam@dynamic@decode:field(
                                        <<"context_snapshot"/utf8>>,
                                        gleam@dynamic@decode:optional(
                                            Context_decoder
                                        ),
                                        fun(Context_snapshot) ->
                                            gleam@dynamic@decode:success(
                                                {transition_record,
                                                    From,
                                                    Event,
                                                    To,
                                                    Timestamp,
                                                    Context_snapshot}
                                            )
                                        end
                                    )
                                end
                            )
                        end
                    )
                end
            )
        end
    ).

-file("src/scamper/serialization.gleam", 63).
?DOC(
    " Deserialize a machine from a JSON string and a config.\n"
    " User must provide decoder functions for state, context, and event types.\n"
).
-spec deserialize(
    binary(),
    scamper@config:config(IJR, IJS, IJT),
    gleam@dynamic@decode:decoder(IJR),
    gleam@dynamic@decode:decoder(IJS),
    gleam@dynamic@decode:decoder(IJT)
) -> {ok, scamper:machine(IJR, IJS, IJT)} | {error, serialization_error()}.
deserialize(Data, Config, State_decoder, Context_decoder, Event_decoder) ->
    Record_decoder = build_record_decoder(
        State_decoder,
        Context_decoder,
        Event_decoder
    ),
    Machine_decoder = build_machine_decoder(
        State_decoder,
        Context_decoder,
        Record_decoder
    ),
    _pipe = gleam@json:parse(Data, Machine_decoder),
    _pipe@1 = gleam@result:map_error(_pipe, fun(Err) -> case Err of
                unexpected_end_of_input ->
                    {json_decode_error, <<"Unexpected end of input"/utf8>>};

                {unexpected_byte, B} ->
                    {json_decode_error, <<"Unexpected byte: "/utf8, B/binary>>};

                {unexpected_sequence, S} ->
                    {json_decode_error,
                        <<"Unexpected sequence: "/utf8, S/binary>>};

                {unable_to_decode, _} ->
                    {json_decode_error, <<"Unable to decode JSON"/utf8>>}
            end end),
    gleam@result:map(
        _pipe@1,
        fun(Decoded) ->
            scamper:restore(
                Config,
                erlang:element(2, Decoded),
                erlang:element(3, Decoded),
                erlang:element(6, Decoded),
                erlang:element(4, Decoded),
                erlang:element(5, Decoded)
            )
        end
    ).